Historically, building owners have not had to deal with tenant requirements for supplemental cooling, power and cabling, with the exception of special purpose computer or trading rooms. These special purpose rooms have been dealt with almost as if they were separate structures. Unless a building was occupant owned, a tenant had to deal with these requirements. Now, due to the changes in market economies, frequently landlords are forced to solve problems of substantial increases in power requirements, additional cooling and cable distribution.
As the use of office space has evolved since the development of personal computers (PC), there has been an escalation in the need for and frequency of re-organization and re-configuration of office space. Enormous amounts of effort and study have gone into the planning and design of office space in order to render its use more flexible and sympathetic to user functions. Most of these efforts have been concentrated in modular space planning and systems furniture engineered to accommodate PCs.
Modem day office requirements have placed burdens on heating/cooling, electrical power distribution and cabling systems which were never anticipated when even the most modern office buildings were built. The rates of reorganization and reconfiguration have escalated from about 10% to 15% per year, U.S. averages in the early 1990's, to 35% to 50% in the mid 1990's, with some companies and industries exceeding 100% per year. The technological life expectancy of local and wide area networks cabling and connectors is currently about eighteen months to two years.
Physical concentrations of PCs and other electrical enhancements such as facsimile machines, copiers, printers, scanners, and in particular, the personnel operating the equipment, have placed extra-ordinary burdens on the most sophisticated and powerful heating, ventilating and air conditioning systems. These concentrations of equipment and personnel generated heat are most frequently offset by increasing the velocity of chilled air from overhead diffusers, usually at the expense of other areas, and to the discomfort of personnel.
Traditionally and technically there have been roughly seven predominant methods of distributing heating/cooling, electrical power and cable in horizontal planes from vertical sources, whether from a building core or from other vertical chases. They have been:
1) Through a ceiling plenum;
2) Through the use of conventional raised flooring systems, as have been used in computer rooms;
3) In-floor conduits or proprietary ducts;
4) A combination of plenum and under-floor distribution through rigid conduit into poke-through outlet boxes to the floor above;
5) Through stud and drywall partitions and/or column enclosures;
6) Through power poles; and,
7) Through system furniture panels.
All of these systems require the feeding of electrical power wiring and cabling through studding, systems furniture, in-floor conduit or ducts. Convenient, horizontal retro-feeding of electrical power wiring or cabling through finished stud and dry wall partitions is particularly difficult, costly, disruptive and sometimes, impossible unless sufficient conduit has been pre-installed.
The most flexible and common of these systems has been the use of ceiling plenums. This plenum approach has severe difficulties and limitations. All work must be performed from ladders or scaffolding. Most connections to work surfaces must be through stud and dry wall partitions or so-called power poles vertically to work surface or floor levels and then distributed horizontally using more stud and dry wall partitions, systems furniture or in-floor conduit or duct.
Once additional power is in place, an undesirable result is a comparable increase in generated heat, requiring more cooling. Typically such additional heat loads have not been anticipated nor dealt with in the base building design or construction.
Localized cooling solutions are being dealt with by trying to increase the output of existing systems such as pushing more air by using higher blower velocities. Increases in air velocities result in increased noise levels and are really nothing more than cycling air more rapidly through the base system which has a finite heat absorbing capacity.
There have been proposals for retrofitted auxiliary flooring systems all of which suffer distinct disadvantages. With one proposal, a lower forced air plenum would be provided for conducting supplemental cooling air to a workspace where heat generating electronic equipment has been installed. Other flooring components would be formed to define enclosed ducts above the air plenum for power cables and communication conductors. It is necessary that these enclosed ducts have imperforate walls to prevent spread of an electrical fire. In the event of such a fire, the egress of the supplemental conditioning air from the plenum would obviously be undesirable. It is for these reasons that building codes require all wiring be encased in fire resistant conduit.
Prior proposals for supplemental flooring systems have all been excessively complex such that they required skilled installers for disproportionately long periods of time. Further, prior proposed systems have not been fully modular and had inadequate provision for access to service lines extending through such a system.
Simple to install supplemental flooring systems which will accommodate power cable, communication wiring, and supplemental cooling to meet the demands of both current day and future electronic equipment are described and claimed in Applicant's U.S. Pat. No. 6,061,982 issued May 16, 2000; U.S. Pat. No. 6,508,037 issued Jan. 21, 2003; and U.S. Pat. No. 6,857,230 issued Feb. 22, 2005, each entitled Raised Flooring System & Method and each is incorporated herein by reference. As systems described in the patents have been developed, a need has evolved for a more economical and expeditious setup floor panel assembly having an increased forgiveness to deviations in panel orientation and in cumulative tolerances for attachment. In addition, a need has developed for increasing the structural integrity of the floor systems by providing a locking method and apparatus that allows for quick assembly, yet more secure and resistant to racking and forces imposed on the system.